Cardiomyocyte Selective Medium (CSM) is a complete medium designed for the purification of cardiomyocyte cells derived from human pluripotent stem cells (hPSC). Current protocols allow for the differentiation of hPSC to cardiomyocytes at a high efficiency, however, the derived cells are a mixed population containing non-cardiomyocyte cells. The non-cardiomyocyte cells may interfere with downstream analyses. Density-gradient centrifugation, genetic modification, and cell sorting based on cell surface markers or mitochondria dyes have been applied to enrich for the hPSC-derived cardiomyocytes. These methods, however, either involve complicated procedures or require special equipment, and are not ideal for therapeutic purposes. Based on the unique metabolic properties of fetal and hPSC-derived cardiomyocytes, which can use lactate as a major energy source, CSM is developed to enrich for the hPSC-derived cardiomyocytes using an efficient, easy, and non-invasive approach. This product is for research use only. It is not approved for human or animal use, or for application in in vitro diagnostic procedures.